Telephone-service system



F. M. SLOUGH. TELEPHONE SERVICE SYSTEM. APPLICATION FILED NOV. 1, 1918.

1,391,588. PatentedSept. 20, 1921.

2 SHEETSSHEET I.

INVENTOR F. M. SLOUGH.

TELEPHONE SERVICE SYSTEM.

APPLICATION FILED NOV. 1, 191a.

. 1,391,588. PatentedSept- 20,1921.

2 SHEETS-SHEET 2.

INVENTOR CORPORATION OF NEW YORK.

UNITED. STATES PATENT OFFICE} FRANK M. SLOUGH, OF ROCHESTER, NEW YORK, ASSIGNOR TO THE STROMBERG-CARL- I SON TELEPHONE MANUFACTURING COMPANY OF ROCHESTER, NEW YORK, A.

TEIJEPHONE-SERVICE SYSTEM.

Specification of Letters Patent. Patented Sept, 20, 1921. Original application filed June 11, 1917, Serial No. 174,1 54. Divided and this application filed November 1, 1918. Serial 1masaeaa.

To all whom it may concern;

Be it 'known that I, FRANK M. SLOUGH, a citizen of the United States residing in Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Telephone- Service Systems, of which the following is a specification.

My-invention relates to the measurement of telephonic service, and has more ularly to do with the selective indication and selective registration of telephonic calls originating in any one of the subscribers stations connected with and served by a single telephone line. i

This application is a division of my copending application, Serial No. 174,154, filed June 11, 1917; I

Where charges for telephonic'service are based upon the number of calls made by a subscriber and several subscribers stations are served by the same telephoneline, it becomes necessary in order correctly to apportion the charges among the various subscribers to provide for ascertaining at which one of the several stations 'ofthe' line each call originates so that it may be entered up or charged against that station and, when vthe identity of the calling station has been determined, it is desirable to provide suitable registering mechanism associated with the lines for enabling the calls of the different stations to be separately recorded and totaled.

In accordance with the embodiment of my invention herein described and illustrated, I provide at 'the'central ofiice and associated with the line circuit to which are connected a plurality of telephones, registers, one for each of the telephones connected to the lines, and I furthermore provide central'oflice apparatus adapted to be associated with the connecting circuit which at the time is used to complete the connection from the said line to a called line which operating in conjunction with the aforesaid registers and controlled by suitable resistance 'coils at each of the substations, serves to selectively register each call made, and to indicate visually to the'operator which of the stations has initiated the call. I furthermore providevisual indicating means common to a plurality of connecting circuits under the particcontrol of the operator, for indicating to the operator at any time during a connection which of the parties of a party line has initiated the call.

Some of the central ofiice controlling ap paratus before mentioned, is individual to the connecting circuit used in completing the connection, the greater part of the apparatus however, is common to an operator s position, or common to a plurality of connectin circuits.

provide means also to remove the reslstance c011 lncluded 1n the line circuit of Referring to the drawings, Figure shows a line to which are connected four substations leading to a line circuit at the main exchange. At the main exchange this line circuit iscomposed of a line and a cutoff relay, and in addition eight register controlling relays whosefunctions W111 be later'described; associated with these register controlling relays which are 'n pairs, are four registers corresponding eac "toone of the stations on the telephone party line.

A connecting circuit is'also shown as indicated at'F, same being provided in the embodiment illustrated, with terminalplugs' at each end for connecting the connecting p ircuit with a calling and a called telephone me. I

In addition to'the relays for performing- T the supervisory listening and ringingcontrol functions which are usual in such conrelays for the purpose of properly controlsol ' necting circuits, I have provided additional ling the selective indication and registration. I

functions, and I have also associated with these relays the aforesaid relays in, order to properly perform these last named func- .tions.

Certain of the relays shown in the figure,

are especially constructed to perform in a certain manner, the construction being more specifically described in my pending appli-, cation, Serial No. 135,636, December 1916; such relays are shown as 11, 12 and 13. Belays of other design, but having equivalent functions may however be employed in their IOO place. These relays have a plurality of armatures and a core extension; one of the armatures magnetically shielding the other.

The shielded armature will not operate until the shielding armature has been fully at- I the strength of current required to operate it must be increased over that required to operate the first or shielding armature. With such a relay as at 11, the first armature will be attracted on a certain value of current, and thereafter the second armature may be operated by intermittent impulses of current, provided the intermittent impulses are of a sufficiently increased value, the value of current suflicient' to operate the first armature being not suflicient to even hold the second armature in its attracted position. I make use of such a relay adjustment only at 11; the relays at 1,2 and 13 being given only such an adjustment as will prevent theshielded armature fromoperating on rapid impulses of current, but the shielded armature will operate on these relays if the current is maintained in the circuit of the relay winding long enough.

Fig. 1 also shows interrupters c c c and 0 which each give a train of impulses com.- prising one long impulse and a varying number of short impulses, these interrupters serving to operate-the relays 11, 12 and 13 according to their, several characteristlcs, and to "produce results as will be later described.

At the substations, resistance coils R R R and R? are provided in the form of electromagnets; these resistance coils being of varlous resistances; the arm'atures for these electromagnets are capable of being manually depressed, and when so depressed the windings of the electromagnets are Operatively connected to the circuit being normally short circuited. When operatively connected the electromagnets will maintain the depressed position of the armature by magnetical attraction until the circuit is opened at the contacts of the relay 15 as will be later described. The registers a, b, c

and d are so constructed that they are not capable of being operated by rapid impulses of current, being sluggish in their action and requiring time to operate.

Fig. 2 shows a portion of the controlling apparatus common to a plurality of connecting circuits, and contains the apparatus required to translate the strength of current flowing into a definite number of step-by-step impulses of current which in turn cause signals to be displayed, and the register system relay 11, conductor 25, conductor 26 of-the of Fig. 1 to be selectively operated aswill be later described.

Fig. 2 shows at Y a balanced relay, the

armature of which stands normally in a mid position between electromagnets, and being controlled by the electromagnets is capable of being moved toward one or the other accordlng to the relative strengths of the group of counting relays in that it is in. effect a step-by-step rheostat current impulse operated, and serves to balance the balanced relay Y for varying line resistances of the lmes to which the apparatusmay be connected.

.- The group Z is the selective group and likewise is a kind of automatic step-by-step current impulse operated rheostat, and serves to balance against the resistance added to the line resistance by the inclusion of such a resistance electromagnet as may be inserted intthe circuit as R R R or R Signal lamps are provided at v16, 17, 18 and 19 common'to the group of connecting circuits served by the apparatus of Flg. 2,

and are selectively operated to indicate which of the parties on the connected party line is operativel connected thereto.

Having thus a ove briefly described some of the apparatus of my invention, I will now to facilitate better understanding of the same, describe its operation in the embodiment illustrated.

In the first place at A, 13,0 and D are shown four substations connected to the limbs of a party line L,. The line wires and the instruments, that is the transmitter and receiver of the instruments shown in the drawing may vary in resistance as they will vary inpractice, and for the sake of description we will assume that the total resistance of the line wires and a calling one of the instruments above mentioned are equal to w ohms. We will assume also that it is the party at B that desires to make a call, and

that the resistance of the electromagnet R at the station B is ohms. The subscriber at B making the call will take his receiver from the hook where it normally rests, and

the hook will thereafter close its contacts in the usual manner to cause the display of the line signal at the main ofiice. A controlling circuit therefor will be closed including the source of current E, conductors 20 and 21, the winding of the line relay 22, conductors 23, the normally closed contacts 240i the line L conductor 27, now closed contacts 28 of the hookswitch of the telephone instru ment at B, the'tran'smitter 29, the receiver 30, the normally closed contacts 31 of the electromagnet R the conductor 32, conductor 33 of the line L,, conductor 34, the normally closed contacts 35 of the relay 11, and thence to ground at G which is connected to the positive pole of the source of current of battery E. Current will therefore flow over this circuit from the battery E energizing the relay 22 which will attract its armature closing its contacts 36 providing an operative circuit for the line "lamp Z, as follows :from the negative pole of source of current E, the conductor 20, conductor 21, the now closed contacts 36 of the relay 22, the conductor 37, the line lamp' l 'the conductor 38, to the ground pole G of battery E. Current will now flow over this circuit 0 erating the signal lamp Z and it will g 0w directin the attention of the operator to the call. T e' operator will then answer the call by inserting the plug P into the jack J of the calling line whereupon connection will be made between the talking limbs of .the line 33 and 26 and the talking limbs of the connecting circuit 39 and 40, also between the winding of the cut-off relay 11 of the line circuit and the local operating strand 41 'of the cord circuit.

The cut-off relay will be operated over a circuit as follows :'from the negative .pole of battery E the conductor 42, the normally closed contacts 43 of the supervisory relay 44, the conductor 45, the conductor 46, the winding of the relay 47, the conductor 48, the cotiperating contacts 49 and 50 of the plug and. jack switch J the conductor 51,

- the winding of the cut-off relay 11, and conductor 52 leading to the round pole G and back to battery E his circuit being closed current will flow over the same energizing the relay 47 and the cut-off relay 11 of the line circuit causin them to attract their armatures, and switch circuits for urposes as will be described. The cut-o relay 11 bein energized will attract its arma tures 53 an 54, but will not attract its armature 55 because this armature is so adjusted as to require an. increased flow of current to operate it as has been above mentioned.

' The arniatures 53 and 54 being attracted will break the contacts 24 and 35 severing the connection of the line battery and line relay 22 with the limbs 34 and 25' of the line. Also a circuit'will beclosed by the making of the contacts 56 for a purpose later to be described.

The circuit of the line relay 22v being opened it will release its armatures opening its contacts 36, and retire the line signal 1. The connecting of the talking conductors 39 and 40 of the connecting circuit to the talking conductors 26 and 33 of the line circuit will cause current to flow over these conduccircuit conductors.v 142 and 40, coiiperating contacts of the plug and jack switch 63 and 64, circuit conductor 26 of the line circuit L circuit conductor 27, the switch contacts 28 of the substation B, transmitter 29, receiver 30, now closed contacts 31 of the substation B, the circuit conductor 32, circuit conductor 33 of the line circuit L coiiperating .contacts 65 and 66, the plug and jack switch P,J circuit conductor 39, circuit conductor 67, circuit conductor 68, circuit conductor, the winding 70 of the relay 59, circuit conductor 71, and from thence to the ground pole of battery E Current flowing over this circuit will energize the answering supervisory relay 59 causing it to attract its armature and close. the contacts 72. The closing of these contacts completes a circuit which ma betracedas follows, it being understoo that the attraction of the armatures of the rela 47 had previously closed contacts 73 and 4; from the negative pole of the source of current at E,, the now closed terg E,. v

u'rrent will now flow over this circuit energizing the relay 79 which will attract its armatures, each of which closes contacts in circuits later to be described. If there were no subscriber onthe line L at the time connection was made with this line by the connecting circuit, the supervisory lamp '84 would be lighted through normal contacts 85 of the supervisory relay 59, andf'now closed contacts 73 of the relay 47 inthe well-known manner. The relay 79 being operated, contacts 86, 87 and 88 will be closed for a purpose to be described;. first, the contacts 88 being closed connects the source of battery current E, by means of conductors 89, 6, the conductors 6 of Fig. 2, and from thence to negative battery supply leads of Fig. 2, as will be later more specifically mentioned.

Referring now more particularly to "Fig. 2, at Y is shown whathas been termed a balanced relay. This relayhas a balanced armature 90 standing midway between the poles of the electromagnets 91 and 92, and corresponding contacts 93 and 94. This is the position the armature would take if the electromagnets are equal in strength. However, with the circuits connected up as they;

and prior ito the'operation of the relay iso the normally closed contacts 163 of the relay 164, and from thence to ground at 165.

Over this circuit would pass current from the source of current E The resulting closure of the contacts 94' would be without effect so far as theope ration of any of the circuits is concerned until such arelay is energized as the relay 79 of an associated connecting circuit, such as the connecting circuit shown in Fig. 1 whose operation is being described in connection with the circuits of Fig. 2, and which is designated in the drawing as connecting circuit F. Further the relay 7 9 being operated and battery being supplied to the common .battery supply lead 6 of Fig. 2 as has been described, the closure of contact 94 will complete a circuit for current flow as follows :from the ground pole of battery, the conductor 95, the conductor 96, the armature 90 of the balanced relay Y, the closed contacts 94 thereof, the circuit conductor 97, the normally made contacts 98 of the relay 99, the circuit conductor 100, the winding of the relay 101, circuit conductor 102, circult conductor 103 to the common negative battery supply lead 6 whose further circuit has been previously traced through the contacts 88 of the connecting circuit 79 tonegative pole of battery E,. This will cause-the operation of the relay 101, and this relay will attract its armatures for purposes to e described. First, the contacts 104 ot the relay 1.01 are closed connecting the ground pole of battery through the circuit conductor 105 to the winding of the relay 99 thereby conditioning the relay 99 to operate in series with the relay 101 whenever the short circuit of the relay 99 from ground pole of battery to ground pole of battery through contacts 94 of the balanced relay Y is removed. However, for the moment the magnet'99 being short circuited will remain deenergized. The contacts 106 are also now closed to condition the relays 107 and 108 for operation, which operation will be later described.

The contacts 109 and 110 of the relay 101 are also closed completing a circuit for the windings of the electromagnet 91, which windings are thereby .placed in multiple with the windings 58 and of the relay 59, and therefore the current flowing over the line and through the subscribers instrument will be divided, part of this current flowing as has been described through the windings of the supervisory relay 59, and a part flowing over the divided circuit including conductors 111 and 112, the now closed contacts 86 and 87 of the relay 79 of Fig. 1, the cir- .tive and positive poles of the battery 15 In passing it may be stated that although a number of sources of battery current are shown in the drawing anddesignated by different characters, it is, understood that all may be and are preferred to be the same battery, although different batteries may be used.v But for convenience and simphcity of representation the batteries are shown in many places rather than to show common battery leads leading to a common battery.

ing placed in parallel therefore with the windings of the relay net 91 will be energlzed in proportion to the flow, of current over the line wires leading to the subscribers station, and will exert a pull upon the armature 90 tending The windings of the electromagnet 91 be- 59, the electromagto withdraw it from the position adjacent to the core of the electromagnet 92, and to cause it to close contacts 93 instead of contacts 94. At this point in the operation the strength of energization of the magnet 92 is arranged to be very yveak as compared with the strength of energization of the magnet 91 when the magnet 91 is connected to any of the lines of the telephone system adapted to operate in connection with the apparatus described. In other words, the efi'ec-t of the resistance of the circuit includingthe winding of the magnet 92 is arranged to be relatively high at this stage of the operation as compared with the effect of the line resistances. Therefore, when the magnet 91 is energized by current over a telephone line as just described, it will first withdraw the armature from the contacts 94 causing it to close contacts 93, this being the invariable operation with any of the lines with-which it is proposed to operate this system. The opening of the contacts .94 destroys the short circuit previously mentioned which had been established around 'the winding of the electromagnet 99 from ground pole of battery to ground pole of battery, and the relay 99 will therefore now be operated over a circuit from the ground,

pole of battery, the now closed contacts 104 of the rela 101, circuit conductor 105, the

winding 0 the rela 99, circuit conductor,

100, the winding 0 the relay'101, circuit conductor 102, circuit conductor 103, and from thence to the negative pole of battery over the previously described circuit to negati e battery including the common battery supply conductor 6. The relay 99 being energized its armature will be attracted and open the contacts 98, and .extend the conductor 97to the conductor 122 by means of now closed contacts 123. However, this closure will be for the present impotent to produce .any operative circuit change since the conductor '97 is now opened at the contacts 94 of the balanced relay Y. .The circuit from the contacts 94 by means of conductor 97 being extended by conductor 122 for a purpose later to be described and operative when the contacts 94 are agam closed as will be later described.

The armature 90 being caused to close contacts 93 as above related, a circuit is closed for the flowing of battery current as follows -from the ground pole of battery, circuit conductor 95, circuit conductor 96,

the armature 90 of the balanced relay Y,

now closed contacts 93 thereof, circuit conductor 124, the normally closed contacts 125 of the relay 126, circuit conductor 127, the winding of the relay 108, circuitconductor 109, the now closed contacts 106 of the previously operated relay '101, circuitfconduotor 128. circuit conductor 129,

circuit conductor 130, circuit conductor 103,-

.and from thence to battery over the common battery supply conductor 6 whose circuit has been previously traced through contacts 88 of the connecting circuit relay 79 to the negative pole of battery. The relay 108 will therefore be operated by current flowing over the circuit just traced including its winding and the source of current, and it will attract its armatures producing circuit changes to "be described. The contacts 131 are now closed conditioning a circuit for the winding'giiof the relay 126, which winding will for'g'the'present however, be short circuited; by having ground pole of battery connected to the opposite sides of the' winding through contacts 131 of the relay 108 on the one side, and through contacts 125 ofthe relay 126, and through contacts 93 of the balanced relay Y on the other side. This short eirc-uit will remain about the winding of the relay 126 until the contacts 93 are later opened as will be later described, and at which time the winding of the relay 126 will be connected in circuit with the. relay 108 as will be later described.

When the relay 108 was energized the contacts 132'and 133 were also closed. The closing of the contacts 133 completes the circuit of the winding of the relay 107 as follows :'from the ground pole of battery,

the contacts 133 of the relay 108," circuitcon ductor 13 1 and the winding of the, relay 107, circuit. conductor 135, the contacts 106 of the relay 101, circuit conductors 128,129, 130, 103, and common negative battery conductor 6 leading to negative battery as has 'therefore at this'sta'ge of theoperation these been described. Thus will the relay 107. be' operated attracting its armaturesand closing contacts 136 and 137.

The closing of these contacts connects the operators circuit shown at O to the talking conductors of the connecting circuit which as has been described are now connected to the subscribers telephone over the subscribers line circuit, the connection being extended from the operators circuit -to the talking conductors of the connecting circuit by means of conductors 138 and 139, contacts 136 and 137 of the relay 107, conductors 140 and 141, contacts 109' and 110 of the relay 101, conductors 4 and 5 of Fig. 1, the now closed contacts 86 and 87 of the connecting circuit relay 79, conductors 111 and 112, the normally closed pairs of contacts' 62 of the releasing relay 15, and from thence by means of conductors 67 and 142 to the talking strands of the connecting circuit 39 and 40; and from thence to the subscribers station. The operator is thus placed in conversational circuit with the subscriber and can request the number of the line desired in order to make connection. While she is. doing this, the apparatus of Fig. 2 is performing the line balancing function, namely-balancing the apparatus of Fig. 2 for the particular line resistance of 95 the calling line including line wires, telephone substation apparatus of'the calling station, etc. This is necessary because many lines vary-considerably in resistance also the telephone substation apparatus may vary in resistance, and it is desired to reduce all of the lines to a common basis be fore proceeding :further with the operation of the system.

The balancing function isperformed byf1 5 the neductionof the resistance of the cir-' cuit of the winding of the magnet 92. This is accomplished by operating a certain number of the relays of the group X, and

relays are operated one at a time-,until sufficient resistance has been out out-of; thecircuit by the short circuiting of th'eljproper number ofresistance coils 146 to 1611; inclusive. This is done as follows: 'Whenthe relay 108 was operated its. contacts 132 were closed and a circuit completed including the intermittent contact makeror interrupter I, and the relays'of the group X in sequence, operating these relays in order, 12

---the operated relays being operatively ;locked after being energized, each of thef relays short circuiting oneof the resistance coils above mentioned when the relay isenergized. The method. of operatin these're- 12 lays and the circuits to cause t eir opera tion will now be described. The first circuit completed leads from the ground pole of battery conductor 166, the segment 16 of the interupter I, the'brush 168, conductor 180 169, now made contacts 132 of the relay 108, circuit conductor 170, normally made contacts 171 of the relay 172, circuit conducf tor 173, now made contacts 174 of the relay r126, circuit conductor 175, now closed contacts 176 of the relay 17 7, circuit conductor 178, circuit conductor 179, the winding of the relay 180', circuit conductor 181, circuit conductors 182,183, 129, 130, 103, and the common battery supply conducto 6 leading to conductor 6 of Fig. '1, through now closed contacts 88 of the relay 79 to the negative ole of battery E Thus will the relay 180 eoperated bycurrent flowing over this circuit and through its winding and will attract its' armature closing its contacts. The right hand-contact being closed Wlll condition the relay 177for operation whenever the segment 167 of the interrupter I of the magnet 92 of the balancing relayY,

thereby strengthening the energiz'ation of this magnet a-definite amount. We will assume that it does not strengthen it enough to cause it to withdraw the armature 90 of the rela Y from its position where it contacts-wlth the contact -93. In such-a case the intermittent interrupter I will revolve I until the connection between the conductor 166 and the conductor 169 by means of the brush 168 and the segment 167 is broken,

' whereupon theshort circuit will be removed [from about the winding of the relay 177,

and the relay 177 will thereupon be energized, attracting its armatures for purposes later to be described.

The energizing circuit for the :relay 177 ing of the relay. 177, circuit conductor 179,

the winding of the relay 180, circuit conductor 181, and from thence to negative battery and over the path which has been previously described, comprising in part the conductors 182, 183, 129, 130, 103, conductor 6, etc. The relay 17 7 thus being energized by current flowing over this circuit and attracting its armatures. will cause an additional reduction of resistance in the i circuit'of the magnet 92 by the closing of contacts 185 which short circuits resistance coil 154. We will assume that the increased flow of current through the winding of the magnet 92 resulting from the short circuiting of this additional resistance coil 15a is still insufiicient to cause this magnet. to-

be sufiiciently energized so as to withdraw The armature of the relay 177 being at- I tracted will break the contacts 176 and close contacts 187, extending the circuit including the interrupter I from the pair of relays 180-177 to the pair of relays 188-189, and the interrupter continuing 'to revolve and again causing the segment 167 to contact with the brush 168, a circuit will be closed comprising the winding of the relay 188, and which circuit is very nearly the same as that previously described upon the winding of the relay 180, the circuit being as follows :--from the ground pole of battery, the conductor 166, segment 167 of the interrupter I, brush 168, circuit conductor 169, contacts 132 of the relay 108, circuit conductor 1.70, normally closed. contacts 171'of the relay 172, circuit conductor 173, normally closed contacts 174 of the relay 126, circuit 'conductor175, now closed contacts 187 of the relay 177, normally closed contacts 190 of the relay 189, circuit conductors 191 and 192, the winding of the relay 188, circuit conductors 193, 182, 183, 129,130, 103, 6, e of Fig. 1, and the now closed contacts 88 of the relay 79 and conductor 89 to the negative pole of battery E Over this circuit current will flow from the source E energizing the relay 188 which will now attract its armatures, just as was the case with the relay 180 of the first pair of relays 180177. conditioning a circuit for. the subsequent operation of the second relay 189 of the pair and short circuiting the resistance 152 in the circuit of the magnet 92. The relay 189 is for the present inoperative because of the short circuit "about its -winding, comprising in part the contacting brush and segment of the interrupter I, just aswas the case in the relay 177 of the first pair of relays, and the relay 189 will be subsequently operated whenever the interrupter I interrupts the circuit of the short circuiting conductor leading to the ground 'pole of'battery. i

Assuming that the energization due to the short circuit of. the resistance 152 is still insufiicientto operatively change the position'of the armature 90 of the balanced relay Y, the interrupter I breaking the circuit of'the conductor leading to it will cause the relay 189 to operate in a manner which will .now be understood, and in turn the circuit of the conductor 175 will be extended to the pair of relays 194 and 195 which will in turn short circuit their associated resistances 151 and 156, and. this action will continue with successive pairs of relays-such as 196-197,198199 until enough of the associated resistance coils allfof which are serially connected in the circuit of the winding of the magnet 92 of the balancing re lay Y have been cut out of this circuit thereby increasing the flow of current sufficient to cause the balancing relay Y to operatively move the armature 90 of the balan over-balanced condition of the relay Y,

the number of coils necessary to be cut out depending upon the resistance of the line and circuit conductors, and apparatus'contained therein. Exact balance is not required.

The opening of the contacts 93 removes the restraining short circuit about the winding of the relay 126 previously noted, and the relay 126 will attract its armatures for the purposes to be related later; the energizing circuit for the relay 126 leading from the ground pole of battery, circuit conductor 208, the now closed contacts 131 of the relay 108, the windin of the 'relay 126, circuit conductor 127, t e winding of the relay 108, circuit conductor l09,the now closed contacts 106 of the relay 101, circuit conduc- I tors 128, 129, 130, 103, 6, 6 of Fig. 1, the now closed contacts 88 of the relay 7 9, and circuit conductor .89 leading to the negative pole of battery E Over this circuit current will flow energizing the relay 126. The contacts 174'leading to the group of relays 'X will now be opened, these contacts being interrelay are again posed in the circuit conductors leading to the group of relays X from the interrupter I so that. the group of relays X will be from now on in the operation of the system unaffected from the interrupter I.

Conductor 124 is now disconnected by the breaking of the contacts 125 of the relay 126 from the windingof the relays 126 and '108, and is extended by means of circuit conductor 201 and-now made contacts to form ca permanent energizing circuit for the rescribed.- 1

An energi'zlng circuit is now closed 'for I the signal lamp 203 as follows':-from the ound pole of batter, now closed contacts of the relay 126, the slgnal lamp 203, circuit conductors 205, 6,6 of Fig. 1, the now closed contacts 88 of the relay 79, and circuit conductor 89 to the negative pole of battery E Current will flow over this circuit energizing I the signal lamp 203 and apprising the operator that she is'operatively connected to tacts 31 will remain 0 closed as will be later dethe telephone line to which she had previously made connection with the plug P of the cord circuit F; and apprising her that the balancing function is complete.

The operator will now upon observing the signal lamp 203 which is now lighted, advise the calling subscriber' to depress his register button, such as226 if it is the station B calling, and this being donethe short circuit about the winding-.11 formed by contacts 31 of the button 226 will be removed, and the button 226 being in part an armature for the electromagnet R the key will remain depressed as long as battery from over the line flows through the winding of the resistance electromagnet R and the conn as long ascurrent flows over the line. he depressing of this button will add to the resistances included 'in the line conductorv 32 by an amount resistance of the electromagnet will be a measure to indicate which of. the stations is calling; the method of translating this measure will be now described. Theline resistance being thus increased, the current through the windings of the electromagnet 91 which is in circuit with the line will be decreased, and the contacts 94 of the balanced relay Y will be again closed.

This completes a circuit forthe relay 164 as foll0w-s:from the ground pole of battery, conductor 95, conductor 96', armature 90, the now closed contacts 94 of the balanced relay Y, conductor 97, now closed contacts 123 of the relay 99, circuit conductor 122, normally closed contacts 227 of the relay 228, circuit conductors 229 and 230, the winding of the relay 164, circuit conductor 231', 129, 130,.103, 6, 6 of Fig.1, now closed contacts 88 of the relay 79, and thence over conductor 89 to negative pole of battery E,.

Current flowing over this circuit will cause.

the relay 164 to be energized and will attract its armatures, and close contacts 219 and opencontacts 163. The closure of the contacts 219 will condition a circuit for the operation of the relay 228 whenever the short circuit placed about the winding of the relay 228 has been removed by the further operation ofthe contacts of the balancing relay Y. This short circuit' comprises the ground pole of battery placed on either side of the winding by means of contacts 94 of the balancing rela Y, and contacts 219 of the relay 164. Tlie relay 228 is therefore inoperative until this short circuit is removed aswill be later described, when the contacts 94 of the balancing relay Y are opened. The contacts 163 now being broken cause a sudden increase to be effected in the resistance of. the associated circuit of the l winding of the 'electroma 'et 92 of the balancing relay Y, this sud en increase 1n resistance being the operative inclusion of the resistance coils 232 to 247 inclusive. The circuit of the conductor 162 normally leading through contacts 163 of the relay 164 to the ground pole of batte belng interrupted, the circuit of the con uctor 162 now leads to ground through all of the resistance coils 232 to 247 inclusive.

In the system of my invention the sum of these resistance coils 232 to 247 inclusive is arranged to be sufficiently hi h that it W111 more than counter-balance t 0 effect upon the balanced relay -Y, produced b the inclusion of any of the resistances and R in the circuit of the electromagnet 91 of the balancing relay Y. Therefore, the balancing relay Y will now be afiected by the inclusion of this added resistance in the circuit of the electromagnet 92 to so decrease the energization of the electromagnet 9'2 that the electromagnet 91 will be overpowering in its effect upon the armature 90, the contacts 94 of the balancing relay Y will be opened, and then the contacts 93 will be closed. The opening of the contacts 94 removes the short circuit which'has been de scribed as having .been placed about the winding of the relay 228 so that the relay 228 is operated, its windin bein placed in serial circuit with the win ing 0 the relay 164 across the poles of. battery. The energizing circuit now being from'the ound pole ofbattery, contact 165, closed contacts 219 of the relay 164, conduct/M220, the winding of the relay 228, conductor 230, the winding of the relay 164, conductor 231, and from thence to negative 'pole-jof battery over conductor 129, 130, 103, 6,6}jof Fig. '1,- contacts 88 of the relay 79, and circuit conductor 89.

The relay .228 being qpemmd will break the contacts 227, thus opening the extended circuit of the contacts that they will no longer be effective .in-tjh'e operation of the system, and the contacts'221 will be closed completing a circuit fromflithe negative, pole of battery from the common battery supply conductor 6 to the winding of the relay 17 2 as follows :-negative battery supply conductor 6, conductors 129- 222, the contacts 221, circuit conductor 223, the windin' of the relay 17 2, and from thence over con uctors 224 and 225, normally made contacts 248 of the relay 249,.conductor 201, closed contacts of the relay 126, conductor 124, through the just closed contacts 93 of the balancing relay Y, the armature thereof, circuit conductor 96, conductor 95 to the ground pole of battery. -This will cause the relay 172 to be operated extendin the circuit leadin from the ground po e of bat tery throng the interrupter I, to the group of relays Z. These relays are now in operative c rcuit arranged to be sequentially operated one at a time in a manner identical rom the ground pole of battery, conductor 166, the segment 167 of the interrupter I,-

the brush 168 thereof, the conductor 169, the now closed contacts 132 of the relay 108, circuit conductor 170, now closed contacts 250 of the relay 172, normally closed contacts 251 oi the relay 249, circuit conductor 252 leading to the armature 253 of the relay 254, and thence to normally closed contacts 255 thereof over circuit conductor 256, through thewinding of the relay 257, the conductor 258, the conductor 183,- and from thence to the common negative battery supply con-- ductor 6 by'means of conductors 129, 130 and 103. J-

In passing it will be seen that the common negative battery supply conductor 6 controlled bycontacts 88 of the relay 79 of Fig. 1 controls the entire connection with I negative ,battery of all the circuits local to -Fig'. 2, and these circuits will therefore be restoredrto normal whenever these contacts .8 am 0 ed.

The circuit just traced for the rela 257 establishes a path for battery throug the interrupter I, and this interrupter W111 operate this relay, and in turn'the associated relay 254 and later, relays 259, 260, 261 2162, etc., or until enough-of these relays of t e 246, 234, 245, etc. have been short circuited; and the resistance of the entire circuit in which they are included sufiiciently decreased to allow a suflicient current to, flow over this circuit and through the winding of the elec-' tromagnet 92 to cause this eledzromagnet to up Z have been operated, and enough of t e associated resistances 232, 247, 233,

overpower the effect of theelectromagent 91, at which time circuit. changes will be efiected as will be later 'relatedti One of these circuit changes is the removal of the short circuit heretofore existing about the winding of the relay 249, 'consisting in part of the circuit conductor 225, the contacts 248 of the relay 249, 'circuit conductor 201, contacts 202 of the relay 126, circuit conductor 124, contacts 93 ofthe balancing relay '-Y and the armature 90 thereof. which is connected to the ground pole of the" source of current. The armature 90 in response to the current flowing through the electromagnet 92, before described, breaks the contacts 93 and the short circuit about the winding of the relay 249 is removed and the relay 249 is thereby operated in series with the relay 172 and closed contacts thereof.

At the time the relayv 249 was operated contacts 263 will condition for operation the signal lamps 19, 18, 17 and 16 whose circuit. will'be completely established upon the operation of the proper number of the relays of the group Z 257, 254, 259, 260, 261, 262, etc.. as will be'later related. The lighting of the signal lamp 264 is an indication to the operator that the subscriber has obeyed instructions and has depressed the registration button.

lVe will assume for the sake of description that when the resistances 232, 247, 233, 246, 234, 245, 235 and 244 have been short circuited by their associated relays that the elimination of the resistances 0 these coils is enough to cause the balancing rela' to again be momentarily balanced, there ore, the amount of resistance contained in these coils is a rough measure of the amount of resistance added to the circuit of the telephone line by the inclusion of the resistance clectromagnet R of the substation, and

therefore, again the number of operated relays associated with these resistance coils, each of which short circuits its associated resistance coil, is also a rough measure of the resistance 7 of the coil R Now lamps 19, 18, 17 and 16 are operatively connected across theterminals of the battery, th 'particular lamp connected depending upon the particular number of relays of the group Z which are opened. As the relays 257, 254, 259, 260, .etc., are successively operated, the lamps 19 18 1.7 and 16 or some of them depending upon the number of relays operated will be successively flashed. With the assumption that the relays 257, 254; 259, 260, 261, 262, 266 and 267 alone are operated to cause the balanced condition of th relay Y then signal lamp 18 will be continuously connected across the terminals of battery over a circuit as follows :-from the ground pole of battery, conductor 208, conductor 265, the contacts 263 of the relay 249, circuit conductor 269, now made contacts .270 of the relay 254, the now made contacts 271 of the relay 260, the now madecontacts 272 of the relay 262, the now made contacts 273 of the relay 267, the normally made contacts 274 of the relay 275, circuit conductor 276, the signal lamp)18,circuit conductor 277, circuit conductor 258, circuit conductor 183, circuit conductors 130, 103, the common negative battery supply conductor 6, and from thence to the negative pole of battery through the controlling contacts 88-of the relay 79 of Fig. 1.

It will be seen that if the relay 275 had also been'operated it would be the lamp 17 which would remain lighted, and in like manner either of the other lamps 16 or 19 might have remained lighted dependingupon the number of the relays of the group Z operated; At the time the lamps 19, 18, etc., are successively flashed there will be a momentary flow of current over divided circuits of these lamps, including conductors 10, 9, 8 or 7 as the case may be depending upon the number of relays operated, and the 580 successive momentary current impulses transmitted over these conductors will becarried. through the contacts 298, 278, 299 and 300, or a certain number of these contacts successively, operating relays 287, 280, 286 and 285 or a certain number of these relays. Such of these relays as may beoperated will belocked. in circuit through their own contacts, and over circuit conductors individual to the connecting circuit F.

. Assuming as we have, that only the re- Y lays 257, 254, 259,, 260, 261, 262, 266 and 267 are operated to balance the relay Y, then in such a case the relays 287 and 280 will be successively operated and locked in circuit, the relays 286 and 285 remaining inert. The first armature of the relay 287- will be operated closing contacts 282 which establishesa locking circuit. for the relay 287 independent of the circuits of Fig. 2; and individual to the connecting circuit F traced as follows :-from the ground pole to battery E the now closed contacts 74 of the relay 47, conductor 284, the now made contacts 282 of the relay 287, the winding of the relay 287, and circuit conductor 281 leading to the negative pole of battery E,,. Current flowing over this circuit will keep the relay 287 energized until the connection is taken down, and the relay 47 de'elnergized and its contacts 74 released. The relay 280 will also close its first pair of contacts 301 which will establish a like looking circuit over the same conductors as the locking circuit for the relay 287, and these two relays will in like manner remain energized for the balance of the connection. The relays 280 and 287 also attracted their right armatures switching circuits later to be described.

It will be seen that the particular substation on the line L calling by the particular resistance coil R R R or R, of the substation which has been inserted in the as will be later described to properly regiscalling. Also included in the connecting circuit F being used, are operated a certain number of the individualized relays 285, 286, 280 and 287. Under the assumptions we are making in this description, the relays 287 and 280 are operated to control selective circuits as will be later described.

During this period the operator is in conversational circuit with the subscriber 'and having learnedlthe number of the line desired, will thereupon make the usual busy test by touching the .tip of the plug P. to the thimble of the jack J and if the line is busy battery potential will be found upon the thimble of this jack and will be carried through a winding inductively linked with the operators telephone set over a circuit comprising conductor 206, contacts 207, conductor 209, contacts 210 of the relay 82, circuit conductor 211, 3, 3 of Fig. 2, the winding of the busy test relay 212, and from thence to the ground pole of battery. If

the line is busy the flow of current over this circuit in the ordinary way will attract the armature of this relay causing current to flow from the ground pole of battery, the now closed contacts 214 of the relay 212,

V conductor 215, the Winding 216 of the induction coil 217, conductor 218 leading to the negative pole of battery E,. This flow of current will be momentarily translated through the circuit comprising the winding- 219 of the induction coil 217 and the operators received 220, and cause a' click to be heard by the operator apprising her that the line is busy. If the line is busy the operator will so apprise the subscriber and will withdraw the plug P fromthe jack J 1 retoring all of the circuits to normal condition.

However, if the line is not busy the operator will insert the plug P in the jack J of. the called-for line making connection therewith, and she will furthermore de ress the ringin key K to ring the calle -for subscriber, and-the depressal of this'key will also operate contacts K assisting in the etablishing of the ringing condition as will be later decribed.

If the called-for line is a party line, which we will assume is not the case in this description, other of the'ringing keys such as form of automatic ms.- The circuits. thereof will be scribed.

When the plug P was inserted into the jack J 2 a circuit was established local to the exchange as follows from the ground pole of battery, the winding of the relay 288, conductor 290, conductor 291,"the thimble 292 of the jack- J the shank 293 of the plug P conductor 294, the winding of the relay 82, and conductor 42 leading to the negative pole of battery E Current will flow over this circuit energizing relays 82 and 288 which. will attract their armatures switching circuits later to be described.

The relay 288 is the. original cut-off relay of the called line L and its armatures bein syste later briefly vdueattracted will break contacts 296 and 29 I termed the common negative batterv supply conductor for the localcircuits of Fig. 2,

and these circuits will therefore all be restored to normal.

The conductors 3, 4,5,6, 7, 8, 9 and 10 which lead through contacts 86, 87, 300, 299, 278, 298 and 88 of the'relay 79 all being broken at these contacts and the circuits controlled over these conductors asshown in Fig.2 will all be restored to normal.

The relays 287 and 280 reviously mentioned as being operated tii 298 and 278 of the relay '79 will remain operated overthe loca locking circuit previ-.

ously described. I

The operator havin de ressed the articular selective key 1%, K,, of- 4 to ring the desired party, for instance, the key K to ring the bell of the substation H on the line L which line is an individual line, the contacts 302 will be closed on the ke K and the contacts of'the key K also be momentarily closed. The last named' contacts bein closed '.a circuit will be formed as fol owsz-from the ground le of battery through the contacts of the ey K, circuit conductor 303, the winding of the ringing relay 208, the circuit conductor 304, the resistance coil 305, the normally made contacts 3060f the relay -44, circu t conductor 307, the now closed contacts 308 of the relay 82, circuit'conductor 309, cirrough contacts K K, or K will bev depressed conne ting' cuit conductor 77, now-closed contacts 72 difi'erent ringing generators .as G G G or Gr will be connected to the circuit of the line depending upon which key is depressed.

z The ringing-circuits illustrated are not new and are not claimed as such in this application, being the ordlnary harmonic selective party line system associated with a common of the relay 59, the circuit conductor 76,-

, mentarily closed contacts K of the ringing 314, or the generator Gr and interrupter 314,

and from thence over the circuit conductor L 315 through contacts 302 of the key K through the series contacts 316 of the other keys over circuit conductor 317, the winding of the trip relay 318, circuit conductor 319, the now made contacts 207 of the, relay 208, circuit conductor 206 to the tip of the plug P and the cooperating tip spring of the jack J over the limb 322 of the line L through the bell and condenser'of the substation H over the line conductors 323 leading to the sleeve spring of the jack J and from thence to the cooperating sleeve of the plug P thecircuit conductor 325 now 'ClOSed right contacts of the relay 208 the resistance coil 329, and circuit conductor 42 to the negative pole of battery E The bell of the subscriber will continue to ring until the response of the called-for albscriber who responds by taking his receiver from the hook bridging the line conductors 322 and 323 by his telephone set comprising a transmitter and receiver 331, whereupon the relay 318 will effectively short circuit the winding of the relay 208 by means of the contacts of.the relay 318, and the re: lay 208 will release its armatures, and the locking circuit for the relay comprising con tacts 333 will be broken. The talking strands of the cord circuit will be connected through from the plug P to the plug P the circuit comprising in part the contacts 207 of the relay 208, and the condensers 334 and 335, and the conductors 39 and 40. Also a path for the supplying of talking battery to the substation transmitter of the substation H will now be complete traced as fol lows :-from the ground pole of battery, the left-hand winding of the relay 44, circuit conductor 337, and now closed contacts 338 of the relay 82, circuit conductor 209, the normally closed contacts 207 of the relay 208, the circuit conductor 206 lead ing to the ti of the plug P the tip spring of the jack line conductor 322, the substation transmitter and receiver 331 of the substation H, line conductor 323, the sleeve ipring of the jack J the sleeve of the plug conductor 325, circuit conductor 341, the right-hand winding of the relay 44, conductor 42 leading to the negative pole of battery E The relay 44 is the supervisory The circuits are so arranged as willbe derelay and will now be energized by current flowlng over the circuit just traced and will attract its armatures switching circuits to be described. First the contacts 306 ofthe relay44will be broken preventing the operator from ringing on the subscribers line while the subscriber is on the line, this in the well-known way by interrupting the circuit of the relay 208. Also the left contacts of the relay 44 will be closed completing a circuit including a particular one a of the commutators c c c and 0 used to perform the register selection and register operation functions. Since I assume that it is the substation B on the calling line which initiated the connection and that by the act of the B subscriber depressing the button 226 of his instrument, the resistance coil R automatically operated the relays 287 and 280 of the cord circuit the commutator 05 will be effective to perform the above functions. The first circuit effected thereby is as follows :from the negative pole of battery E circuit conductor 343, circuit conductor 344, the commutator c and as the commutator revolves we will assume that the brush thereof 346 comes first into contact with the segment 347, and thereafter the segment 348 and later 349,- the insulating segment 350, and finally the 95 conducting segment 351.

It will be seenthat certain of the segments, namely, 351, 347 and 348 make, contact with the brush 346 for a very short period of time, and that the segment 349 is wider and will therefore make contact for a relatively longer period of time. The insulating segment 350 will also make contact with the brush for a relatively long period of-time.

scribed so that no operative function will be performed therein during the revolution "of the commutator until the large conducting segment 349 makes contact with the brush 7 346, and thereafter each of the segments will perform an operative function. For instance, assume now that the segment 347 makes quick passing contact with the brush 346, the circuit which I have started to describe will pass through this quick passing contact and through the brush 346, and over circuit conductor 352, the normally made contacts of the relay 286, the now made contacts 354 of the relay 280, the now made contacts 355 of the relay 287, circuit con- .ductor 356, the now made contacts of the relay 44, circuit conductor 357, the normally closed contacts 358 of the relay 359, circuit conductor 360 through the winding of the relay 12, through contacts 362 and circuit conductor 83 to the ground pole of battery. Current will flow over this circuit including the winding of the relay 12, and it will attract its quick acting armature 363only, and as this armature does not perform any operative function so far as the circuits are concerned its operation will be futile.

The slow actin armature 364 bein shielded bythe quick acting armature 363, or being made slow acting in any other suitable manner, will not be attracted by the quick impulse of current passed through the short contact 347, nor will it be operative by impulse of current passed by the other contact 348, but later when the long contact 349 passes current to the brush 346 contact will be made for a long enough time to fully operate the armature. 364 to cause it to'close contact 365, thus conditioning the relay 359 for operation, but which relay at the present time will not be operated due to there being a short circuit placed about its winding by the segment 349 leading to the negative pole of battery.

The contacts 365 of the vrelay 12 will close another circuit however for the relay 15 traced as follows-:-from the ground pole of battery, the winding of the relay 15, the

normally made contacts 426 of the relay- 359, the now closed contacts 365 of the relay 12 and circuit conductors 366, 344 and 343 to the negative pole of battery E Current flowing over this circuit Will'operate relay 15 attracting its armatures and breaking contacts 62 which will interrupt the flow of battery current to the subscribers instrument and through the resistance electromagnet R, which has been described as at the time energized maintaining contacts 31 opened, and the supply of current being interrupted by the contacts 62, the electromagnet B, will be deenergized restoring the short circuiting contacts 31 to normal operative condition, and the substation instrument will be connect rto the line wires instead of through/ .ie resistance of the coil R Now later upon the commutator 0 advancing to the position wherein the brush 346 rests upon the wide insulating segment 350, the relay 359 will be operated over a circuit traced as follows :--from the negative pole of battery E circuit conductors 343, 344, and 366, the now closed contacts 365 of the relay 12, circuit conductor 368, the winding of the relay 359, circuit conductor 360, the winding of the relay 12, now closed contacts- 362 of the relay 82,.circuit conductor 83, and from thence to the ground pole of battery. The relays 359 and 12 will thus be locked in operative circuit and both will maintain their armatures attracted. The circuit of the impulse transmitting wire from commutator 0 is now extended to the relay 13 by means of now made contacts 369 of the relay 359 circuit conductor 370, normally closed contacts 371, circuit conductor 372, the winding of the relay 13, circuit conductor 361, the now closed contacts 362 of the relay 82, and

from the nc'e to the ground pole of battery.

.The contacts 426 of the relay 359 will now be opened restoring the relay 15 to normal position and reconnecting the source of battery supply to the subscribers line. The

times when the commutator c, is in circuit with it, and the contacts 375 being thus rapidly closed will complete a circuit com prising the high voltage direct current generator G and electroresponsive apparatus 1n the circuit of the line as will be later described. The circuit is traced as follows from the round pole of the high voltage generator 5 through the .said'generator en-' tering by way of the opposite pole'and line by way of the negative pole thereof,'ci rcuit conductor 376, the intermittently closed contacts 375 of the relay 13, the normally closed contacts 378. of the relay 379, the now closed contacts 381 of the supervisory relay 44, circuit conductor 45, and for the major portion of the current, the circuit conductor 46, the winding of the relay 47, circuit conductor 48, circuit conductor 41, the shank 49 of the answering plug P the coiperating thimble 50 of the jack J of the calling line, the circuit conductor 51, the winding of the cutoff relay 11, and the circuit conductor 52 to ground. This will cause a considerably increased current to flow over the circuit including the winding of the cut-off relay 11, and the relay 11 will operate its slow armature 55 once for each vof the short segments 351, 347 and 348 of the commutator 0 The armature 55 thus responding tothe rapid impulses of current, contacts 382 will be intermittently and rapidly operated to operate in sequence the relays 383, 384, 385, 386, 387 and 388, and if there are enough impulses, 389 and'390. s

The number of impulses, and therefore the number of these relays operated will depend upon which one of the commutators 0,, 0,, 0 or c, is included in the impulse sending circuit just described.

eWe will now describe the circuits involved in the operation of the relays under the assumption that it is the commutator 0,, which is included in the impulse Sending circuit. In such a case there will be three rapid impulses of current followed by a relatively ong impulse of current followed in turn by a relatively long break in the current flow.

impulses, the relay 383 will be operated over a circuit traced as follows :-from the I n 0 operated by current over this clrcult and will attract its armatures, closin contacts 394 and 395. The contacts 395 bem closed will condition a circuit for the rel ay 384, which circuit will be operative when the intermittently made contacts 382 are opened which will happen after the first rapid impulse.

The circuit then for the winding of the relay 384 can be traced from the ound pole of battery, contacts 56 of the re ay 11,

circuit conductor 396, the contacts 395 of the relay 383, circuit conductor 397, the

winding of the rela 384, circuit conductor 392, the winding 0 the relay 383; circuit conductors 393, 21 and 20-leading to the negative pole of battery EL: Therefore the relay 384 will operate b flow of current over this' circuit, and wil attract its armatures immediately after the operation of the relay 383, and will by contacts 399 extend the circuit controlled by the impulse sending contacts 382 to the next pair of relays 385 and 386. The second closure of the contacts 382 in response to the second rapid impulse of current through the relay 11 will cause the relay 385 to be operated over a circuit traced as follows ':-from the ground pole of battery, the contacts 382 of the relay 11, the now madecontacts 399 of the relay 384, the normally closed contacts 400 of the relay 386, the winding of the relay 385, circuit conductor 21", and circuit conductor 20 to the negative pole of battery E. The relay 385 will'thus be operated attracting its armatures'and closing contacts 402 and 406. The contact; 402 being operated will condition a circuit for the relay 386, which relay will be: operated immediately thereafter when the'contacts 382 are opened. Current will flow over a circuit traced as follows including the winding of the relay 386, from the ground pole of bat tery, contacts 56 of the relay 11, circuit conductor 396, contacts 402 of the relay 385, circuit conductor 404, the winding of the relay 386, the Winding ofthe -relay 385, and circuitconductors21-and 20 to the negative pole of battery E. The relay 386 will thereupon be operated attracting its armatures.

The first armature breaks contacts 405 in the circuit of the register a and prevents the register a from operating which it would otherwise do because of the previous closure of the contacts 406 of the relay 385. The contacts 405 break the circuit however before the slow acting register a can operate.

ing contacts 382 is now extended by means register .5 however will not have time to operate because the third rapid impulse of current will be followed by an opening of the controlling contacts 382 which will permit the heretofore short circuited relay 388 to immediately operate breaking the contacts 410 'in the circuit of the slow acting register I). The relay 388 being operated in the same manner as was the relay 386 and in the same manner as the relay 384 the operation ofwhich relays has been reviously escribed, will extend the impu se. sending crrcuit controlled by the contacts 382 to the next pair of relays 389 and 390.

By referring now to the commutator c, it will. be seen as has been said, after the contact has been made, that the three rapid contacts 351, 347 and 348 will be followed by a long contact. This will now produce a long operative closure of the contacts 382 of the relay 11, and will operate the relay 389 for a relatively long period of time over a circuit traced as follows :from the ground pole of battery,,. c'ontacts 382 of the relay 11, contacts 399 of the relay 384, the contacts 407 of the relay 386, the contacts 411 of the relay 388, the normally made contacts 412 of the relay 390, the winding of the relay 389, and circuit conductors 21 and 20 to the negative pole of battery. This will operate the relay 389 for a longer period of time than was the case with the relays 383, 385 and 387, and the relay 389 will close its contacts 413 and 414. The contacts 413 I being closed will complete a circuit for the cperatlon of the register 0 as follows from the ground pole of battery, the contacts 56 of the relay 11,-circuit' conductor 415, closed contacts-414 of therelay 389, circuit conductor 416, the normally closed contacts 417 of the relayj390, circuit conductor 418, the register a, and circuit conductor 20 to negative pole of battery E.

y This circuit will be closed for a long enough period to enable the slow acting register 0 to operate, and this register will operate to register the connection against [the account of the particular calling subtions A, C or D on the line L The commutator 0 when the rapid contacts thereof were being made, as has been descri described, operated rapid acting armature 373-producing rapid closure of thecontacts 375. When the wide segment 349 makes contact with the brush 346, the contacts 375 will remain closed for the'duration of this contact, and in addition the, slow acting armature 374 will be operated to close the contact 419, and the closure of this contact will condition the rela 379 for operation, it being kept inoperative for the duration of the contact 'ust mentioned by reason of the fact that t e' segment 349 com letesa short'circuit about the winding of t e relay 37 9. Later however, the wide segment hav-'- infi passed the brush 346 there will be a re tlvely long insulated segment 350 pass under thebrush 346, and the short circuit about the winding of the relay 37 9 is thereby removed and this relay will operate attractg itgefirmatures for purposes to be later The operating circuit for the relay 379 is as follows :-from the negative pole of bat; tery E,, thecircuit conductors 343, 344 and 366,- the now closed contacts 419 ofthe relay 13, the winding of the rela 37 9, circuit conductor 372, the winding the relay 13, the l now closed contacts 362 of the rela 82, and

circuit conductor 83 to the groun pole of battery.- j

' The contacts 371- in the impulse sendin circuit from the interrupter brush 346 winow .be opened disablingthis interrupter until the operator takes down the connection.

The contacts 378 of relay 379 will be broken interruptin the circuit of the high voltage generator which as has been described previous to this time as connected in'the circuit of the cut-off relay 11, to intermit: tently operate the contacts 382. Therefore,

- the contacts-382-will be opened for the balance of the connection, and the opening of these contacts will interrupt the short circuit which has been operative about the windin' of. the .relay 390, and the relay 390 wil be operated interrupting the circuit of the re ister 0 at contacts 417 Contacts 422 o the relay 379 will be closed to-short circuit the resistance coil in the circuit of the relay 47, this being, done bplacing a negativebattery potential on t e opposite side, of the resistance coil to which, negative battery potential has been connected so that a short circuit of the windin ensues. The circuit-by which this negatlve battery potential is laced about the winding 423 is traced as fo lows :-from the negative pole of battery E circuit conductor 424,' contacts 422 of the relay 379,

- contacts 381 and circuit conductor 45 leading to the resistance coil 423. The subscribers are now in conversational circuit. An emergency listening key 501 is arranged in the usual manner so that the the substation B on' L, that is calling, and

therefore that the relays 280 and 287 of the cord circuit are operated-during the conversational period, the lamp A, will thus be operatively connected to the contacts 502 over a circuit traced as follows :-from the ound pole of battery, contacts 502 of the ey 501, circuit conductor 503, the now closed contacts 504 of the relay 287, the now closed contacts 505 of the relay 280, normally closed contacts 506 of the relay 286, circuit conductor 507, the signal lamp A, and circuit conductor 343 to the negative pole of battery E The signal lamp therefore whenever the key 501 is depressed will light the lamp corresponding to the substation of the line calling. The group of lamps A A A and A, are, arranged to be common to a plurality of connecting circuits and made operative when a key of any of the connicting circuits is operated to indicate whic of the parties of the party line initiated the call. After the conversation of the subscribers has been finished, the subscribers will restore their receivers to the hooks lightin the disconnected supervisory si al 84 in t e usual manner over a circuit Elm the ground pole of battery, the lamp 84, the contacts 85 of the now retired supervisory relay 59, conductor 76, andcontacts 73 of the relay 47 to the negative pole of battery E 3 The operator will now disconnect the cord circuit by withdrawing the plugs P, and P from the jacks J and J z and all of the circuits .will. be restored to normal, since at the time, the exchange circuits are controlled by the cut-ofi relay 11, cut-oil relay I have in the above description described" certain instrumentalities to attain the objects of my invention, and I am aware that numerous and extensive departures may be made from the same without violating the spirit of the invention, the objects of which are ap arent from the foregoing description.

l l'gat I claim is: 1. n a telephone system, the combination with a telephone line provided'with a plurality of sub-stations, a main station, sald telephone line extending by its limbs from a plurality of the substations to a ma n station, a plurality of signals at the mam station, one for each of the said sub-stations, a lurality of resistances, one at each of the substations, each resistance being of different value from the other substation resistances,

each of the said signals corresponding to a particular substation on the line, and apparatus at the main station under the control of one of the said resistances included in circuit with the line to operate the particular signal to identify the substation whereat said resistance is located.

' 2. In a telephone system, the combination with a telephone line provided with a plurality of substations, a main station, said telephone line, extending by its limbs from a plurality of the substations to a main station, the said telephone line being of appreciable ohmic resistance, a resistance unit tor each of the substations adapted to be included in circuit with the line, the said resistance unit's differing in resistance value,

aplurality of signals at the main station, each. of which corresponds to a particular station on the line, and translating apparatus at the main station, said apparatus being controllable by the said line resistance to condition the said translating apparatus for selective operation of the said. signals, said translating apparatus including means .to cause a subsequently included resistance unit of one of the substations to control said translatin apparatus whereby selective operation o the ro er signal to identify the calling substation is effected.

3. In a telephone system, the combination with a telephone line extending by its limbs from a plurality of substations to a main station, a resistance unit adapted to be inserted in circuit with the line of the said substations, and step-by-step impulse operated electroresponsive means at the main station under the control of the said resistance unit.

4. In an electrical system, the combination of a main station, a plurality of distant stations, a connecting line connecting the said stations, an electro signal at the main station for each of the distant stations, a resistin series, a series of various resistances adapted to be included in said transmitting circuit, a balancin r relay under the control of one of the sai resistances, step-by-step mechanism'under the control of said balancing relay, a plurality of electroresponsive devices, and apparatus associated with said balancing relay to variably control the operation of said step-by-step mechanism under the control of said included variable resistances.

6. In a telephone system, the combination with a telephone line, a substation for said line, a main station for saidline, apparatus at the said substation, said substation apparatus and the said line containing a certain amount of ohmic resistance, a balancing relay at the main station adapted to be connected to the said line, and an electrically controlled step-by-steprheostat including a series of cooperating relays at the main station adapted to be operated under the control of said balancin relay, whereby the ohmic resistance of the said line and substation apparatus can be indicated.

7. In a telephone system, the combination with a telephone line,a substation for said line,'a main station for said line, apparatus at thesaid substation, said substation apparatus and the said line containing a certain amount of ohmic resistance, a balancing relay {at the main station adapted to be connected to the said line, an electrically controlled step-by-step rheostat at the main station adapted to be operated under the control of said balancing relay, whereby the ohmic resistance of the said line and substation apparatus can be indicated, an additional resistance'adapted to be inserted in circuit with the said substation, and a second step-by-step rheostat thereafter adapted to be cate the value of the ohmic resistance of the inserted resistance. 8. In a telephone system, the combination with a telephone line, a substation therefor, a main station, automatic switching mechanism at the main station, means to associate the said line with the said automatic switching mechanism, an electromagnet at the substation, contacts normally .associated with the said electromagnet .and normally shunting the same, manually operated means to interrupt the said shunt circuit, an armature for the said elect'romagnet operated responsive to the breaking of the said circuit under the control of the said electromagnet to control the operation of the said switching mechanism. I

9. In a telephone system, the combinatlon with a telephone line, a substation therefor,

controlled by the balancing relay to india main station, a source of current at the nism at the main station, a control relay therefor, means .to variabl operate the said switching mechanism un er the control of the said control relay, a winding for the said control relay, means to include the said winding in circuit with the said source of current and the line conductors of the said the same, manually operated means to interrupt the said shunt circuit to cause current from the said source flowing over the said telephone line conductors to energize the said electromagnet, an armature for the said electromagnet held operated responsive to the breaking of the said circuit, to maintain the said circuit broken, whereby the re-' sistance of the said electroma at is included in the circuit containing t e said control relay, the said line conductors and the said source of current too rate the said relay, and an armature for t e said control relay adjusted to respond to the inclusion of the said resistance in the said circuit to measurably control the operation of the said switching mechanism.

10, In a telephone system, thecombination with a telephone line, a substation therefor, a main station, a'source of current at the main station and means'at the main station to connect the saidsource of current to .the telephone line, automatic switching mechanism at the main station, a control relay therefor, means to variably o erate the said switching mechanism'ii-iinder t e control of the saidcontrol relay, said control relay, means include the said winding in circuit with the said source of current and the" line conductors of the said telephone line, an electromagnet at the substatlon having a definitdfl-"electrical resistance, contacts normally associated with the the same, manually operatedmeans to interrupt the said shunt circuit to cause current from the said source flowiii'g over the said telephone line conductors to energize the said electromagnet, an armaturefor the said electromagnet held operated responsive to the breaking of the sald circuit, to maintain the said circuit broken, whereby-the resistance of thesaid electromagnet is included in the circuit containing thesaid control relay, the

said line conductors and the said source ofcurrent to operate the said relay, an arma-' ture for the said control relay adjusted to respond tothe inclusion of the sald'resist ance in the said circuit to measurably control the operation of the said switching mechanism, and means subsequently operative responsive to the operation of the said switching mechanism. to open the circuit of the said line-conductors to restore 'trol the operation of the f winding for the substationfor controlling the operation of V 1 115 the said substation electromagnet contacts.

11. In a telephone system; the combination with a telephone line, a substation therefor, a main station, a source of current at the main station. andmeans at the main station to connect the said source of current to the telephone line, automatic switching mechamm at the main station, a control relay therefor, means. to variably operate the said switching mechanism under the control of the said control relay, a windin for the said control relay, meansto inclu e the said winding in circuit with the said source of current and the line conductors of the said telephone line, an electromagnetat the substation having contacts associated with the said electromagnet and normally shunting the same, manually operated means to interrupt sa d shunt'clrcuit to causecurrent from the sand source flowing over the said telephone line conductors to magnet, an armature for the said electromagnet held operated responsive to the breaking-of the said circuit, to maintain the said circuit broken, whereby the resistance of the said electromagnet is included in the a definite electrical resistance,

energize the said electrocircuit containing the said control relay, the

said line conductors and the said source of current to operate the said relay, an armas ture for the said control relay adjusted to respond to the inclusion of the said resist-' ance in the said circuit to measurably consaid switching mechanlsm, and means operative' responsive to the operation of the said control relay to open the line of .the said li!1e conductors to restore the said substation electromagnet contacts.

12. In a telephone system, the combination with a telephone line, substations therefor, a mam statlon, an automatic switch at the H main station, means to associate the said a said electromagnet and normally shunting tomatic switch with calling terminals of the said telephone line, a control r el'ay for the said automatic switch ada' 'tedijwhen 'operated to control the extent of operati on of the said switch, and resistancemeans at. the said the said control relay. l

13. In 'a, telephone system-,- the combination with a telephone line, asubstation therefor, a main station, an automatic. switch at the main station, means to associate the said automatic switch with calling'terminals of the said telephone line, a control relay for the said automatic switch ada ted when operated to control the extent. 0 operation of 1 the said switch, resistance means at the said substation for controlling the operation of the said control relay, manually operated means at the said substation for including said reslstance means 1n circuit with the said one line and control relay, and electrotic means operated responsive to the operation of the said manually operated means to maintain the said resistance means in operative circuit with the said control re- 14. In a telephone system, the combination with a telephone line, a substation therefor,.a main station, an automatic switch at the main station, means to associate the said automatic .switch with calling terminals of the said telephone line, a control relay for the said automatic switch adapted when operated to control the extent of operation ,of the said switch, resistance means at the said telep magn substation for controlling the operation of the said control rela manually operated 'means at the said su station for including said resistance means in circuit with the said telephone line and control relay, electromagnetic means operated responsive to the operation of the said manually operated means to maintain the said resistance means in operative circuit with the said control re lay, and subsequently operating means at the main station to open the circuit of the said telephone line, to restore the said resistance includin means.

15.1n a telep one system, the combina tion with a telephone, line, a substation there: for, a main station, an automatic switch at the main station, means to associate the said automatic switch with calling terminals of the said telephone line, a control relay for the said automatic switch adapted when operated to control the extent of operation of the said switch, resistance means at the said substation for controlling the operation of the said control relay, manually operated means at the said substation for including said resistance means in circuit with the said telephone line and control relay, electromagnetic means operated responsive to the.

operation of the said manually operated means to maintain the said resistance means in operative circuit with the said control relay, subsequently operating means at the main station to open the circuit of the said telephone line, to restore the said resistance including means, and means responsive to the o eration of the said switch to indicate the e cc of o eration thereof.

16. n a tele one system, the combination with a te ephone line, a plurality of substations therefor, a main station, an automatic switch at the main station, means to associate the said automatic switch'with calling terminals of the said telephone line, a control relay, for the said automatic switch adapted when operated to control the extent of operation of the said switch, and resistance means at each of the said substations on the line for controlling the operation of the said control relay.

17. In a; telephone system, the combination with a-telephone line, a plurality of substations-therefor, a main station, an automatic switch at the main station, means to associate the said automatic switch with calling term nals of the said telephone line, a control relay for the said automatic switch adapted when 0 erated to control the extent of operation 0 the said switch, resistance means at each of the said substations on the .line for controlling the operation of the said controlrelay, manually operated means at eachof the said substations for including the associated resistance means in circuit with the said telephone line, and electromagnetic means operatedresponsive to the operation of the manually operated means to maintain the said resistance means inoperative'circuit with the said control relay.

18. In a telephone system, the combination with a tele hone line, a plurality of substations there or, a main station, an automatic switch at the main station, means to associate the said automatic switch with the calling terminals of the said telephone line, a control relay for, the said automatic switch adapted when operated to control the extent of operation of the said switch, resistance means at each of the said substations on the line for controlling the operation of the said control relay, manually operated means at each of the said substations for inmain station to open the circuit of the said telephone line to restore the-operated substation resistance including means.

19. In a telephone system, the combination with a telephone line, a plurality of substations therefor, a main station, an automatic switch at the main station, means to associate the said automatic switch with the calling terminals of the said telephone line, ,a control relay for the said automatic switch adapted when operated to control the extent of operation of the said switch, re-

sistance means at each of the said substations on the line for controlling the operation of the saidcontrol relay, manually operated means at each of the said substations for including the associated resistance means in circuit with the said telephone line, electromagnetic means operated responsive to the operation of the manually operated means to maintain the said resistance means in operative circuit with the said' control relay, subsequently operating means at the main station to open the circuit of the said telephone line to restore the operated substation resistance including means, and

7 means responsive to the operation of the said switch to indicate'the degree of operation thereof.

20. In a tele hone system, the; combination with a te ephone line, a plurality of tion of the said control relay, manually operated means at each of the said substations for including the associated resistance means in circuit with the said telephoneline, electromagnetic means operated responsive to the operation of the manually operated means to maintain the said resistance means in operative circuit with the said control .relay, subsequently operating means at the main station to open the circuit of the said telephone line to restore the operated substation resistance including means, means responsive to theoperation "of the said switch to indicate the degree of'operation thereof, and signal indicating means at the main station under the control of the said switch to indicate a calling substation.

21. In combination, an electrically operated step-by-step rheostat, abalance controlling circuit therefor having two branches, electric resistance in each branch, means to unbalance the said circuit by manually including a resistance in one of the branches,

and means responsive thereto to cause the operation of the said rheostat, contacts for the said rheostat and operated thereby to again balance the said circuit by excluding vresistance from the second branch thereof,

and means responsive to the balancing by the said rheostat to discontinuethe operation thereof.

In witness whereof, I hereunto subscribe my name this 31st day of October, A. D.

FRANK M. SLOUGH. 

